Variable capacity refrigerant compressors have been utilized in automotive air conditioning systems, with the compressor capacity being controlled by a control valve that is either pneumatically-operated or electrically-operated. In either case, the control valve typically varies the pressure in a crankcase of the compressor to control the compressor capacity. In a particularly economical arrangement, the compressor includes an internal bleed passage coupling the crankcase to suction (low-side) refrigerant pressure, and the control valve controls refrigerant flow though a control passage coupling the crankcase to discharge (high-side) refrigerant pressure by controlling the position of a plunger relative to the control passage. In pneumatically-operated control valves, the plunger is positioned by a bellows or diaphragm that is responsive to suction pressure, whereas in electrically-operated control valves, the plunger is positioned by the armature of a solenoid that is energized by a system controller. In general, pneumatically-operated control valves offer superior stability, while electrically-operated control valves offer superior flexibility. Accordingly, it has been proposed to integrate both pneumatic and electric control elements into a single control valve to obtain inherently stable and flexible suction pressure control. In such integrated control valves, the pneumatic control element establishes a predefined regulation setpoint for the suction pressure, and the electric control element is variably energized to bias the pneumatic element, effectively adjusting the regulation setpoint. See, for example, the U.S. Pat. Nos. 6,439,858 and 6,126,405, which are incorporated herein by reference.